다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Achieving a higher dissymmetry factor is a crucial issue in developing circularly polarized luminescence (CPL) materials. Here, by tailoring the solvent composition and the morphology of the same chiral emissive small molecules (R- or S-SPAn), circularly polarized emission with a boosted dissymmetry factor (two orders) was realized. It was found that by regulating the water fraction in the mixed THF/H2O, we were able to achieve kinetic control over association of chiral emissive R- or S-SPAn into various nanostructures with 0D nanospheres, 2D nanoflakes and 3D stacked nanoflakes. These nanostructures are all CPL active. Remarkably, the dissymmetry factors of the nanostructures were significantly enhanced compared to those of the molecules and further boosted in different morphologies, from ∼10−4 (0D nanospheres) to 10−3 (2D flake) to ∼10−2 (3D nanoflakes). The enlarged glum value could be assigned to a good packing induced strong luminescence of an excimer. This strategy provides an efficient way to fabricate higher dissymmetry factor CPL organic nanomaterials by only changing the supramolecular architectures while using the same chiral small molecules.

/pdf/boosting-the-circularly-polarized-luminescence-of-small-3vpju71v8q.pdf

Boosting the circularly polarized luminescence of small organic molecules via multi-dimensional morphology control

It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers.

Advances in self-assembly and regulation of aromatic carboxylic acid derivatives at HOPG interface

Self-assembled behaviors of three fluorenone derivatives substituted by different halogen atoms, 2-(pentadecyloxy)-6-bromo-fluorenone (Br-FC15), 2-(pentadecyloxy)-6-chloro-fluorenone (Cl-FC15), and...

Halogen Substituent Effects on Concentration-Controlled Self-Assembly of Fluorenone Derivatives: Halogen Bond versus Hydrogen Bond

Two-dimensional supramolecular assemblies of a series of 2,7-bis(10-n-alkoxycarbonyl-decyloxy)-9-fluorenone derivatives (BAF-Cn, n = 1, 3-6) consisting of polar fluorenone moieties and ester alkoxy chains were investigated by scanning tunneling microscopy on highly oriented pyrolytic graphite surfaces. The chain-length effect was observed in the self-assembly of BAF-Cn. Self-assembly of BAF-C1 was composed of a linear I pattern, where the side chains adopted a fully interdigitated arrangement. As the length of side chains increased, the coexistence of a linear I pattern and a cyclic pattern for the self-assembly of BAF-C3 was observed. Upon increasing the length of the alkoxy chain even further (n = 4-6), another linear II structure was observed in the BAF-Cn monolayer, in which the side chains in adjacent rows were arranged in a tail-to-tail configuration. It is reasonable to conclude that not only the van der Waals forces but also the dipole-dipole interactions from both the fluorenone cores and the ester alkoxy chains play critical roles in the self-assemblies of BAF-Cn. Our work provides detailed insights into the effect of intermolecular dipole-dipole and van der Waals interactions on the monolayer morphology of fluorenone derivatives.

Cooperating dipole–dipole and van der Waals interactions driven 2D self-assembly of fluorenone derivatives: ester chain length effect

A systematic investigation on the bromine substituent position effects on the self-assembly of fluorenone derivatives 1-bromo-7-(pentadecyloxy)-fluorenone (1-BFC15), 2-(pentadecyloxy)-7-bromo-fluor...

Bromine Substituent Position Triggered Halogen versus Hydrogen Bond in 2D Self-Assembly of Fluorenone Derivatives

Host–guest self-assemblies of methyl 5-bromo-2-(hexadecyloxy)benzoate (host) and 1-bromohexadecane (guest) molecules were investigated at the liquid/solid interface by scanning tunneling microscopy. Polar solvent (1-octanoic acid) and nonpolar solvents (1-phenyloctane, n-pentadecane, n-tetradecane, and n-decane) were selected to study the solvent effect on the self-assembly of the host–guest system. It is observed that the host–guest system self-assembles into different morphologies at low concentrations due to the solvent adsorption. Only a linear structure can be obtained at high concentration in different kinds of solvents. In particular, the different self-assembled patterns obtained at low concentration will eventually transform to the same linear structure. Owing to the participation of guest molecules, a strong Br···O═C halogen bond is formed between host and guest molecules, further leading to the occurrence of physisorbed monolayers and structural transition. The density functional theory calcula...

Solvent Effect on Host–Guest Two-Dimensional Self-Assembly Mediated by Halogen Bonding

Three coumarin derivatives (Co16, 6-Br-Co16 and 6,8-Br-Co16) with ester, ether, and carbonyl groups and different numbers of bromine substituents on the coumarin cores were synthesized. Their two-dimensional (2D) self-assemblies were probed by scanning tunneling microscopy (STM) at the liquid–solid interface. The Co16 molecules formed a zigzag lamellar pattern on the HOPG surface through intermolecular H⋯O hydrogen bonds. The 6-Br-Co16 molecule with one Br substituent was found to form a uniform zigzag linear pattern, owing to intermolecular Br⋯OC (ester groups) halogen bonds and H⋯Br hydrogen bonds. The dibromo-substituted 6,8-Br-Co16 molecule could form a dislocated linear pattern, in which the molecules are linked through the Br⋯OC (ester group) halogen bond, and Br⋯Br and H⋯Br bonds. The STM results reveal that the introduction of the Br atom actuates the formation of the Br⋯OC bond instead of the H⋯OC bond, which is the key dominant force to form the different 2D adlayers. At the same time, the cooperation of H⋯Br hydrogen bonds leads to the stability of the nanostructures. DFT calculations were performed to unravel the cooperation and competition mechanism for the formation of halogen bonds and hydrogen bonds in 2D molecular self-assembly.

Juntian Wu

Papers

Halogen Substituent Effects on Concentration-Controlled Self-Assembly of Fluorenone Derivatives: Halogen Bond versus Hydrogen Bond

Cooperating dipole–dipole and van der Waals interactions driven 2D self-assembly of fluorenone derivatives: ester chain length effect

Bromine Substituent Position Triggered Halogen versus Hydrogen Bond in 2D Self-Assembly of Fluorenone Derivatives

Solvent Effect on Host–Guest Two-Dimensional Self-Assembly Mediated by Halogen Bonding

Cooperation and competition of hydrogen and halogen bonds in 2D self-assembled nanostructures based on bromine substituted coumarins